U.S. patent number 6,497,011 [Application Number 10/091,245] was granted by the patent office on 2002-12-24 for vehicle having parts connected with a sealing spring fastener comprising a hermetically closed cavity.
This patent grant is currently assigned to Termax Corporation. Invention is credited to Richard H. Ducato, Mark Fleydervish, Werner Politzki, Michael Walter Smith, Eustathios Vassiliou.
United States Patent |
6,497,011 |
Smith , et al. |
December 24, 2002 |
Vehicle having parts connected with a sealing spring fastener
comprising a hermetically closed cavity
Abstract
This invention relates to vehicles having parts connected with a
sealing spring fastener, which comprises a U-shaped structure, on
which an elastic body has been incorporated. The elastic body has a
hermetically closed cavity within the U-shaped structure. The
sealing spring fastener can form an assembly with an extension of a
panel, preferably a plastic panel. The assembly or the fastener by
itself can be engaged into the slot of a solid sheet, preferably a
metal sheet, in a manner that one side of the sheet is sealed from
the other side of the sheet in the vicinity of the slot. In a
preferred version, the sealing fastener comprises a substantially
non-elastic tough casing around portion of the elastic body in
order to avoid rapture during insertion of the fastener into the
slot.
Inventors: |
Smith; Michael Walter (Lake
Zurich, IL), Ducato; Richard H. (Kenosha, WI),
Fleydervish; Mark (Buffalo Grove, IL), Politzki; Werner
(Hawthorn Woods, IL), Vassiliou; Eustathios (Newark,
DE) |
Assignee: |
Termax Corporation (Schaumburg,
IL)
|
Family
ID: |
27394060 |
Appl.
No.: |
10/091,245 |
Filed: |
March 5, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
747630 |
Dec 22, 2000 |
6381811 |
|
|
|
Current U.S.
Class: |
24/295;
24/289 |
Current CPC
Class: |
F16B
5/0614 (20130101); F16B 2/20 (20130101); Y10T
24/304 (20150115); Y10T 24/307 (20150115); Y10T
24/30 (20150115) |
Current International
Class: |
F16B
5/06 (20060101); F16B 2/20 (20060101); A44B
021/00 (); F16L 033/00 () |
Field of
Search: |
;24/289,293,297,295
;52/716.2,716.5,716.7,716.8,717.04,717.05,717.06 ;411/508,509,510
;277/630,637,640,648,651 ;296/39.1,191 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Sandy; Robert J.
Attorney, Agent or Firm: Vassiliou; E.
Parent Case Text
RELATED APPLICATIONS
This is a Division of Application Ser. No. 09/747,630, filed Dec.
22, 2000 now U.S. Pat. No. 6,381,811, which is incorporated herein
by reference.
Claims
What is claimed is:
1. A vehicle comprising two parts connected with a sealing spring
fastener, the sealing spring fastener comprising: a U-shaped
structure having a first side, a second side, a top end, a bottom
end, an upper section, and a lower section; a spring leg on each
side of the U-shaped structure, extending outwardly from said
U-shaped structure in a general direction from the bottom end
toward the top end, each spring leg having an attached end and a
free end; a casing surrounding at least partially the lower section
of the U-shaped structure, except at least the free end of each
extending leg, the casing enclosing a cavity within the first side
and the second side of said U-shaped structure, the casing having
an upper sector and a lower sector; and an elastic body comprised
of at least a gasket, the gasket extending away from the closed
cavity in the vicinity of the top of the U-shaped structure, the
gasket having an upper side and a lower side; wherein the casing
has lower ultimate elongation, higher Shore hardness, and higher
shear strength than the elastic body.
2. A vehicle as defined in claim 1, wherein the casing is
substantially non-elastic.
3. A vehicle as defined in claim 2, wherein the cavity is formed at
least partially by a portion of the elastic body, said portion of
the elastic body being at least partially surrounded by the
casing.
4. A vehicle as defined in claim 3, wherein the casing comprises a
lip at the upper sector of the casing, the lip being embedded
between the upper side and the lower side of the gasket, and
wherein the lower sector of the casing has emerging sides.
5. A vehicle as defined in claim 3, wherein the casing is suitable
to be attached or bonded to the elastic body.
6. A vehicle as defined in claim 3, wherein the casing comprises a
plastic material which is substantially non-elastic at room
temperature, and the elastic body comprises a compound selected
from a group consisting of thermoplastic elastomer, silicone,
polyurethane, plastisol, and a mixture thereof.
7. A vehicle as defined in claim 6, wherein the U-shaped spring
fastener further comprises barbs inside the closed cavity having a
general direction from the top end toward the bottom end of the
U-shaped structure.
8. A vehicle as defined in claim 6, wherein the sealing spring
fastener further comprises an element selected from a group
consisting essentially of an underseal extending from the elastic
body and disposed under the spring leg, a sealing rib at the lower
side of the gasket, and a combination thereof.
9. A vehicle as defined in claim 3, wherein the U-shaped spring
fastener further comprises barbs inside the closed cavity having a
general direction from the top end toward the bottom end of the
U-shaped structure.
10. A vehicle as defined in claim 3, wherein the sealing spring
fastener further comprises an element selected from a group
consisting essentially of an underseal extending from the elastic
body and disposed under the spring leg, a sealing rib at the lower
side of the gasket, and a combination thereof.
11. A vehicle as defined in claim 2, wherein the casing comprises a
lip at the upper sector of the casing, the lip being embedded
between the upper side and the lower side of the gasket, and
wherein the lower sector of the casing has emerging sides.
12. A vehicle as defined in claim 11, wherein the sealing spring
fastener further comprises an element selected from a group
consisting essentially of an underseal extending from the elastic
body and disposed under the spring leg, a sealing rib at the lower
side of the gasket, and a combination thereof.
13. A vehicle as defined in claim 2, wherein the casing is suitable
to be attached or bonded to the elastic body.
14. A vehicle as defined in claim 2, wherein the U-shaped spring
fastener further comprises barbs inside the closed cavity having a
general direction from the top end toward the bottom end of the
U-shaped structure.
15. A vehicle as defined in clam 14, wherein the sealing spring
fastener further comprises an element selected from a group
consisting essentially of an underseal extending from the elastic
body and disposed under the spring leg, a sealing rib at the lower
side of the gasket, and a combination thereof.
16. A vehicle as defined in claim 2, wherein the sealing spring
fastener further comprises an element selected from a group
consisting essentially of an underseal extending from the elastic
body and disposed under the spring leg, a sealing rib at the lower
side of the gasket, and a combination thereof.
17. A vehicle as defined in claim 11, wherein the cavity is formed
at least partially by a portion of the elastic body, said portion
of the elastic body being at least partially surrounded by the
casing.
18. A vehicle as defined in claim 3, wherein the sealing spring
fastener further comprises an element selected from a group
consisting essentially of an underseal extending from the elastic
body and disposed under the spring leg, a sealing rib at the lower
side of the gasket, and a combination thereof.
19. A vehicle as defined in claim 11, wherein the casing comprises
a plastic material which is substantially non-elastic at room
temperature, and the elastic body comprises a compound selected
from a group consisting of thermoplastic elastomer, silicone,
polyurethane, plastisol, and a mixture thereof.
20. A vehicle as defined in claim 19, wherein the sealing spring
fastener further comprises an element selected from a group
consisting essentially of an underseal extending from the elastic
body and disposed under the spring leg, a sealing rib at the lower
side of the gasket, and a combination thereof.
21. A vehicle as defined in claim 11, wherein the U-shaped spring
fastener further comprises barbs inside the closed cavity having a
general direction from the top end toward the bottom end of the
U-shaped structure.
22. A vehicle as defined in claim 21, wherein the sealing spring
fastener further comprises an element selected from a group
consisting essentially of an underseal extending from the elastic
body and disposed under the spring leg, a sealing rib at the lower
side of the gasket, and a combination thereof.
23. A vehicle as defined in claim 1, wherein the sealing spring
fastener further comprises an element selected from a group
consisting essentially of an underseal extending from the elastic
body and disposed under the spring leg, a sealing rib at the lower
side of the gasket, and a combination thereof.
24. A vehicle as defined in claim 15, wherein the fastener further
comprises at least one sealing rim disposed at the bottom of the
gasket.
25. A vehicle as defined in claim 1, wherein the fastener further
comprises at least one sealing rim disposed at the bottom of the
gasket.
26. A vehicle as defined in claim 25, wherein the elastic body is
selected from thermoplastic elastomer, silicone, polyurethane,
plastisol, and a mixture thereof.
27. A vehicle as defined in claim 24, wherein the gasket is
disposed substantially under the top end of the U-shaped
structure.
28. A vehicle as defined in claim 27, wherein the elastic body is
selected from thermoplastic elastomer, silicone, polyurethane,
plastisol, and a mixture thereof.
29. A vehicle as defined in claim 24, wherein the elastic body is
selected from thermoplastic elastomer, silicone, polyurethane,
plastisol, and a mixture thereof.
Description
FIELD OF THE INVENTION
This invention relates to spring fasteners, vehicles having parts
connected with and more particularly those fasteners which are
suitable to be engaged in a slot of a solid sheet and support the
extension of a panel in a manner that one side of the solid sheet
is sealed from the other side around the slot.
BACKGROUND OF THE INVENTION
A number of fasteners have been used in the past for securing one
object on another object, as for example, securing an article such
as for example a plastic sheet on a metal or other rigid plastic
sheet. However, the fasteners being used presently are particularly
designed for only a limited number of matching objects to be
secured on each other. For sealing purposes, a secondary resilient
sheet, or a resilient body attached to the fastener may be
used.
Examples of conventional fasteners are disclosed in U.S. Pat. No.
5,987,714 (Smith); U.S. Pat. No. 5,887,319 (Smith); U.S. Pat. No.
5,542,158 (Gronau et al.); U.S. Pat. No. 5,422,789 (Fisher et al.),
U.S. Pat. No. 5,373,611 (Murata); U.S. Pat. No. 5,314,280
(Gagliardi); U.S. Pat. No. 5,095,592 (Doerfling); U.S. Pat. No.
4,792,475 (Bien); U.S. Pat. No. 4,683,622 (Ohelke); U.S. Pat. No.
4,609,170 (Schnabl); U.S. Pat. No. 4,245,652 (Kelly et al.); U.S.
Pat. No. 3,864,789 (Leitner); U.S. Pat. No. 3,673,643 (Kindell);
U.S. Pat. No. 3,525,129 (Holton); U.S. Pat. No. 2,825,948 (Parkin);
U.S. Pat. No. 2,607,971 (Bedford, Jr.); U.S. Pat. No. 2,542,883
(Tinnerman); U.S. Pat. No. 2,329,688 (Bedford, Jr.); U.S. Pat. No.
2,322,656 (Murphy), among others.
U.S. Pat. No. 5,887,319; U.S. Pat. No. 5,987,714; patent
application Ser. No. 09/493,476, filed Jan. 28, 2000; patent
application Ser. No. 09/494,112, filed Jan. 28, 2000; and patent
application Ser. No. 09/493,304, filed Jan. 28, 2000; describe
fasteners suitable to be used in a slot, and they are all
incorporated herein by reference.
SUMMARY OF THE INVENTION
As aforementioned, this invention relates to vehicles having parts
connected with spring fasteners characterized by a structure
suitable to be engaged in a slot. More particularly, this invention
pertains a sealing spring fastener comprising: a U-shaped structure
having a first side, a second side, a top end and a bottom end; a
spring leg on each side of the U-shaped structure, extending
outwardly from said U-shaped structure in a general direction from
the bottom end toward the top end, each spring leg having an
attached end and a free end; and an elastic body integrally molded
on the U-shaped structure at least with the top end, except at
least the free end of each extending leg, the elastic body having a
closed cavity within the first side and the second side of said
U-shaped structure.
It is important that the elastic body comprises an underseal
extending under each spring leg. In other words, the underseal is
an extension of the elastic body.
The elastic body further comprises a gasket extending away from the
closed cavity in the vicinity of the top end. It is also important
that the gasket comprises at least one sealing rim, thus improving
considerably the sealing properties of the gasket.
The elastic body preferably comprises a compound selected from a
group consisting of thermoplastic elastomer, silicone,
polyurethane, plastisol, and a mixture thereof. More preferably,
the elastic body comprises a thermoplastic elastomer, and even more
preferably the elastic body has been molded by insert injection
molding.
The free end of each leg is engageable with a slot of a solid
sheet. The gasket seals the top of the slot upon engagement of the
free end of each slot with the slot of said solid sheet.
The sealing fastener of the present invention preferably further
comprises barbs inside the closed cavity having a general direction
from the top end toward the bottom end of the U-shaped
structure.
The present invention also pertains a vehicle comprising two parts
connected with a sealing spring fastener, the sealing fastener
comprising: a U-shaped structure having a first side, a second
side, a top end, a bottom end, an upper section, and a lower
section; a spring leg on each side of the U-shaped structure,
extending outwardly from said U-shaped structure in a general
direction from the bottom end toward the top end, each spring leg
having an attached end and a free end; a casing surrounding at
least partially the lower section of the U-shaped structure, except
at least the free end of each extending leg, the casing enclosing a
cavity within the first side and the second side of said U-shaped
structure, the casing having an upper sector and a lower sector;
and an elastic body comprised of at least a gasket, the gasket
extending away from the closed cavity in the vicinity of the top of
the U-shaped structure, the gasket having an upper side and a lower
side; wherein the casing has lower ultimate elongation, higher
Shore hardness, and higher shear strength than the elastic
body.
Preferably, the casing has lower ultimate elongation, higher Shore
hardness, and higher shear strength than the elastic body. Even
more preferably, the casing is substantially non-elastic.
Preferably, the cavity is formed at least partially by a portion of
the elastic body, said portion of the elastic body being at least
partially surrounded by the casing.
The casing may comprise a lip at the upper sector of the casing,
the lip being embedded between the upper side and the lower side of
the gasket, and the lower sector of the casing may comprise
emerging sides. Further, the casing is suitable to be attached or
bonded to the elastic body.
The casing may preferably comprise a plastic material which is
substantially non-elastic at room temperature, and preferably the
elastic body comprises a compound selected from a group consisting
of thermoplastic elastomer, silicone, polyurethane, plastisol, and
a mixture thereof. Nylon 6,6, preferably containing lubricant, is
preferred as the molding material for the casing, while
thermoplastic elastomers are preferred as the elastic body.
As also mentioned above, the sealing fastener may further comprise
barbs inside the closed cavity having a general direction from the
top end toward the bottom end of the U-shaped structure. Further,
the barbs are preferably bent for stronger holding or exertion
force, as described and claimed in provisional application No.
60/118,046 filed Feb. 1, 1999 and patent application Ser. No.
09/482,714, filed Jan. 13, 2000, both of which are incorporated
herein by reference.
Further, this invention is related to a method of making the
sealing spring fasteners described above. This method comprises
steps of. (a) forming the U-shaped structure; (b) forming the
casing; (c) inserting the U-shaped structure into an insert mold;
(d) inserting the casing over the U-shaped structure in the insert
mold; (e) molding the elastic body in said insert mold, thereby
forming the sealing spring fastener.
The steps (c) and (d) may be replaced by steps: (c') making an
assembly by inserting the U-shaped structure into the casing; and
(d') inserting the assembly into the insert mold.
This invention also relates to an assembly of a panel having an
extension and a sealing spring fastener, according to any of the
variations described above, wherein the extension of the panel is
inserted into the closed cavity.
This invention also relates to a vehicle comprising two objects
connected with any of the fasteners in any of the variations
described above.
DESCRIPTION OF THE DRAWING
The reader's understanding of practical implementation of preferred
embodiments of the invention will be enhanced by reference to the
following detailed description taken in conjunction with perusal of
the drawing figures, wherein:
FIG. 1 illustrates a composite cross-sectional view of a sealing
spring fastener according to a preferred embodiment of the present
invention.
FIG. 2 shows a perspective view of a part of the fastener of FIG. 1
without the elastic body.
FIG. 3 shows a perspective view of the spring fastener of FIG.
1
FIG. 4 shows another perspective view of the spring fastener of
FIG. 1
FIG. 5 is a composite cross-sectional view of an assembly of the
extension of a panel and the fastener of FIG. 1, wherein the
extension is inserted into the closed cavity of the fastener.
FIG. 6 is a composite cross-sectional view of the fastener of FIG.
1 engaged into a slot of a solid sheet.
FIG. 7 is a composite cross-sectional view of the assembly of FIG.
5 engaged into a slot of a solid sheet.
FIG. 8 is a composite cross-sectional view of an assembly similar
to that of FIG. 5 engaged into a slot of a solid sheet, wherein the
free ends of the legs remain within the slot.
FIG. 9 is a perspective view of the fastener of FIG. 1, in which
the elastic body of the fastener comprises an underseal under the
spring legs, and sealing rims in the lower side of the gasket.
FIG. 10 is a composite cross-sectional view of the fastener of FIG.
1, in which the elastic body of the fastener comprises an underseal
under the spring legs, and sealing rims in the lower side of the
gasket.
FIG. 11 is a perspective view of a casing, which is part of the
fastener shown in FIG. 14, according to a preferred embodiment of
the instant invention.
FIG. 12 shows a perspective view of a part of the fastener of FIG.
14 without the casing and the elastic body, and showing lines
through which single cross sections pass.
FIG. 13 shows a perspective view of a part of the fastener of FIG.
14 lacking the casing (including the structure of FIG. 12 and the
elastic body).
FIG. 14 shows a perspective view of a complete sealing spring
fastener according to a preferred embodiment of the present
invention.
FIG. 15 shows a single cross sectional view through line A, shown
in FIGS. 14 and 12.
FIG. 16 shows a single cross sectional view through line B, shown
in FIGS. 14 and 12.
FIG. 16 shows a single cross sectional view through line B, shown
in FIGS. 14 and 12.
FIG. 17 shows a single cross sectional view through line C, shown
in FIGS. 14 and 12.
FIG. 18 shows a side view of another preferred U-shaped structure,
according to this invention, wherein said U-shaped structure is
wider in the vicinity of the bottom end than in the vicinity of the
top end. Further, the barbs originate at a point between the
vicinity of the bottom end and the vicinity of the top end.
NOTE: composite cross sectional view is defined as a number of
superimposed cross sections, parallel to each other, such as for
example the cross sections defined by lines A, B, and C of FIGS. 12
and 14. Single cross sectional view is defined as a cross section
which is defined for example by only one of the lines A, or B, or
C, of FIGS. 12 and 14.
DETAILED DESCRIPTION OF THE INVENTION
As aforementioned, this invention relates to spring fasteners
characterized by a structure suitable to be engaged in a slot and
secure one article on another article.
More specifically, this invention relates to a sealing spring
fastener, which comprises a U-shaped structure, on which an elastic
body has been incorporated. The elastic body has a closed cavity
within the U-shaped structure. The sealing spring fastener can form
an assembly with an extension of a panel, preferably a plastic
panel. The assembly or the fastener by itself can be engaged into
the slot of a solid sheet, preferably a metal sheet, in a manner
that one side of the sheet is sealed from the other side of the
sheet.
Referring now to FIGS. 1-4, there is depicted a sealing spring
fastener 10, according to a preferred embodiment of the present
invention, comprising a U-shaped structure 12 having a first side
14, a second side 16, a top end 18, and a bottom end 20.
On each side 14 and 16 of the U-shaped structure 12 there is a
spring leg 22, extending outwardly from the U-shaped structure 12
in a general direction from the bottom end 20 toward the top end
18. Each spring leg 22 has an attached end 24 and a free end
26.
An elastic body 28 is integrally molded on the U-shaped structure
12 at least under the top end 18, with the exception of at least
the free end 26 of each extending leg 22. The elastic body 28 has a
closed cavity 30 within the first side 14 and the second side 16 of
said U-shaped structure 12. The closed cavity 30 has an opening 31.
The specific definition of a "closed" cavity is that there is no
communication or opening between the cavity and any region outside
the cavity except for the opening 31.
The elastic body preferably extends under each spring leg 22
forming an underseal 52, better shown in FIGS. 9 and 10. This
underseal improves the sealing performance of the fastener when
inserted to a slot of a solid panel as discussed hereinbelow.
The U-shaped structure 12 in the vicinity of the bottom 20,
especially under the attached end 24 of the legs 22, may also be
uncovered (not shown in the figures) by the elastic body 28, as
long as the cavity 30 remains as a closed cavity.
The elastic body may be any elastic material such as for example
plastisol or polyurethane, more preferably silicone, and even more
preferably a thermoplastic elastomer as described in provisional
application No. 60/170,112, filed Dec. 10, 1999, and patent
application Ser. No. 09/561,505, filed apr. 28, 2000, both of which
are incorporated herein by reference. Preferably, the thermoplastic
elastomer is molded by insert injection molding, a technique well
known to the art.
The free end 26 of each leg 22 is engageable with a slot of a solid
sheet The gasket 32 has a lower side 54, which seals the top of the
slot upon engagement of the free end 26 of each leg 22 with the
slot of said solid sheet, as it will be illustrated in detail
hereinbelow. The lower side 54 of the gasket 32 preferably
comprises at least one sealing rim 50, which improves considerably
the sealing properties of the fastener 10 when it engages to the
slot of the solid sheet.
The sealing fastener of the present invention preferably further
comprises barbs 34 inside the closed cavity having a general
direction from the top end 18 toward the bottom end 20 of the
U-shaped structure 12.
The present invention also pertains an assembly of a panel 36,
preferably plastic, which has an extension 38, as better shown in
FIG. 5 in a composite cross section. The extension 38 has
preferably a cross sectional shape commensurate to the shape of
opening 31 of the closed cavity 30, so that the extension 38 can be
inserted through the opening 31, and secured in the closed cavity
30 by the barbs 34.
FIG. 6, shows a composite cross sectional view of the fastener 10
engaged in a slot 40 of a solid sheet 42, preferably a steel sheet,
before insertion of the extension 38 into the closed cavity 30 of
the sealing spring fastener 10.
In operation, it is highly preferable that the sealing spring
fastener 10 is assembled first with the panel 36 by insertion of
the extension 38 into the closed cavity 30, although the fastener
may also be engaged into the slot 40, as shown in FIG. 6, before
formation of the assembly shown in FIG. 5. This is because during
manufacturing the plastic sheet is usually made in one location and
transferred to a different location for being placed and secured on
the solid sheet in the manufacture of a vehicle, such as an
automobile for example. Therefore, it is considerably more
convenient, albeit not necessary, to make the assembly of the panel
36 with the fastener 10 at the location of the manufacture of the
panel 36 and ship it ready for engagement on the sheet 42 at the
location of the final assembly.
The sealing spring fastener 10, after having been assembled with
the panel 36, is engaged in the slot 40 of the solid sheet 42. The
pressure applied on the gasket 32 of the elastic body, due to the
engagement of the legs 22 with the slot 40, seals hermetically said
slot 40, taking also into account that the cavity 30 is a closed
cavity.
The arrangements shown in FIGS. 6 and 7 provide a more secure
engagement of the assembly with the slot 40. However, if
disassembling the arrangement is desired, pulling the panel away
from the solid sheet will usually result in leaving the fastener 10
engaged in the slot 40. On the other hand, if the legs 22 are such
as to provide the engagement shown in FIG. 8, pulling the panel 36
away from the solid sheet will usually result in leaving the
fastener 10 still assembled with the panel 36, provided that the
barbs 34 provide adequate grabbing force on the panel 36. A
preferred type of such barbs is the type described and claimed in
provisional application No. 60/118,046 filed Feb. 1, 1999 and
patent application Ser. No. 09/482,714, filed Jan. 13, 2000, both
of which are incorporated herein by reference.
Also, in order to achieve similar results, the U-shaped structure
12, better shown in FIG. 18, may be wider in the vicinity of the
bottom end 20 than in the vicinity of the top end 18, with rather
short (and therefore less elastic and more robust) barbs between
the vicinity of the bottom end 20 and the vicinity of the top end
18.
For many applications, the elastic body 28 shown in FIGS. 1-10, has
to be selected very carefully, since in order to have better
sealing proprieties, the gasket 32 has to be rather elastic and
soft, while in order to avoid rapture, the lower part under the
spring legs 22 has to be rather non-elastic and rather hard. In
addition, shear strength of the lower part is very important, while
the shear strength of the gasket is considerably less important.
Thus, a compromise has to be reached for workable results. A Shore
hardness in the range of A 30 to A 40, and more preferably in the
range of A 33 to A 37 according to ASTM D 2240, combined with an
ultimate elongation in the range of 100% to 500%, and more
preferably in the range of 150% to 250% according to ASTM D 412,
seem to represent optimum ranges of elastomeric materials, as long
as an adequate shear strength exists Even so, in many cases this
compromise is still unacceptable. The problem of this compromise
becomes more pronounced, since in the Automotive Industry, a
plurality of extensions 38 extending from a plastic panel are to be
inserted in respective slots 40 of a solid or rigid sheet 42, such
as metal sheet for example. Small misalignments, therefore, may
occur easily due to this multiplicity of slots, and may result in
rapture of the lower part of the elastic body under the spring legs
22, as this part is forced through the slots 40.
Examples of commercial thermoplastic elastomers are SANTOPRENE.RTM.
111-35 from Advanced Elastomer Systems, Akron, Ohio, MULTIFLEX.RTM.
40005 and MULTIFLEX.RTM. 30005 from Multibase, Inc., Copley, Ohio,
DYNAFLEX.RTM. 2706, DYNAFLEX.RTM. 6730, and DYNAFLEX.RTM. 7702-9
from GLS Corporation, McHenry, Ill., TEKNOR.RTM. 5000-NT-40 NT and
TEKNOR.RTM. 9000-NT-25 NT from Teknor Apex Company, Pawtucket, R.I.
02861.
The present invention resolves this problem of having to compromise
according to another more preferred embodiment. According to this
embodiment, the gasket is made more elastic and less hard than the
lower part under the spring legs 22. Also, the lower part is made
to have higher shear strength than the gasket. Shear strength is
defined as the stress, usually expressed in pounds per square inch,
required to produce fracture when impressed perpendicularly upon
the cross section of a material. It might be worth mentioning also
that a first material is more elastic than a second material, not
only if it presents higher elongation, but also if its strain or %
elongation is higher than that of the second material when each is
subjected to the same stress.
Elastomers used for the gasket portion of this embodiment are
preferably rather soft, having a Shore hardness in the range of 15
A to 30A.
Thus, according to this embodiment of the instant invention, it is
highly preferable that the part of the elastic body 28 under the
gasket 32 is considerably harder, less elastic, and having a
considerably higher shear strength than the gasket.
One way to achieve this is to provide a casing 60, as better shown
in FIG. 11, to cover the part of a modified elastic body 28' under
the gasket 32. In one example, this casing may be made by
injection-molding of a tough and substantially non-elastic polymer,
such as nylon 66 or modified nylon 66. Zytel.RTM. 101L, 3189, 408L,
ST801, are examples of such resins, which are made by DuPont. Of
course, other types of resins may be used as long as they satisfy
the requirements of the claims.
The casing 60 has a casing body 62 with open portions 64, lips 66,
an upper sector 70, and a lower sector 72. The lips 66, including
the part of the casing body 62 in the vicinity of the lips may have
holes 68, which holes 68 are used for strongly attaching the casing
to the modified elastic body 28', as it will be described later in
more detail. The holes 68 may have any shape, including round,
oblong, oval, etc. The holes may be partially or totally replaced
by roughness of the surface, etching of the surface (with
hydrochloric acid, for example), bends, embosses, etc., all of
which have the purpose make the casing 60 suitable to be attached
or bonded to the modified elastic body 28'. The sides 74 of the
lower sector 72 are merging together.
FIG. 12 shows a U-shaped structure 12 as already described earlier
and shown also in detail in FIG. 4. Lines A, B, and C define
different single cross sections in important and different sections
of the U-shaped structure.
When making the fastener of the present invention, preferably, the
U-shaped structure 12 of FIG. 12 is inserted into the mold, and
then the casing 11 is inserted in a manner to surround said
U-shaped structure 12, so that the spring legs 22 extend through
the cut-off regions 64. Otherwise, the U-shaped structure 12 is
inserted into the casing 60, and the assembly of the two is
inserted and secured in the mold. In sequence, the elastic body is
molded to form the final sealing spring fastener 10' of the present
invention, as better shown in FIG. 14. The elastic body 28'
surrounding the U-shaped structure 12 with the exception of the
spring legs 12 as earlier explained, and in the absence of casing
60, is shown in FIG. 13, for purposes of illustration.
The lip 66 of the casing 60 is secured between the upper side 76
and the lower side 78 of the gasket 32, as better shown in FIGS. 16
and 17.
FIGS. 15, 16 and 17 correspond to single cross sections defined by
lines A, B, and C, respectively, which lines are shown in FIGS. 12
and 14.
For a plurality of applications it is critical that the average
initial (up to 100% elongation) ratio of stress (in p.s.i) to
strain (% elongation) is in the range of about 0.5 to 2 in the case
of the elastic body, while it is preferably in the range of about
one to three orders of magnitude greater in the case of the casing
as compared to that of the elastic body.
The operation of this embodiment is similar to the operation of the
previous embodiments. Due to the tough and substantially
non-elastic characteristics of the casing 60, as well as to the
merging sides, the insertion of said sealing fasteners into metal
or other material slots, does not result in rapture, even under
considerably misalignment conditions.
The term "elastic" in the context of this invention means
"elastomeric" and not just "flexible".
Automobiles or other vehicles may be made, comprising one or more
of the fasteners of the instant invention, providing substantial
improvements regarding safety, performance and comfort.
Examples of embodiments demonstrating the operation of the instant
invention, have now been given for illustration purposes only, and
should not be construed as restricting the scope or limits of this
invention in any way.
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